From: Theodore Ts'o Subject: [PATCH-v2 0/5] add support for a lazytime mount option Date: Sat, 22 Nov 2014 11:54:22 -0500 Message-ID: <1416675267-2191-1-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Ext4 Developers List , Theodore Ts'o , linux-btrfs@vger.kernel.org, xfs@oss.sgi.com To: linux-fsdevel@vger.kernel.org Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com List-Id: linux-ext4.vger.kernel.org This is an updated version of what had originally been an ext4-specific patch which significantly improves performance by lazily writing timestamp updates (and in particular, mtime updates) to disk. The in-memory timestamps are always correct, but they are only written to disk when required for correctness. This provides a huge performance boost for ext4 due to how it handles journalling, but it's valuable for all file systems running on flash storage or drive-managed SMR disks by reducing the metadata write load. So upon request, I've moved the functionality to the VFS layer. Once the /sbin/mount program adds support for MS_LAZYTIME, all file systems should be able to benefit from this optimization. There is still an ext4-specific optimization, which may be applicable for other file systems which store more than one inode in a block, but it will require file system specific code. It is purely optional, however. Please note the changes to update_time() and the new write_time() inode operations functions, which impact btrfs and xfs. The changes are fairly simple, but I would appreciate confirmation from the btrfs and xfs teams that I got things right. Thanks!! Any objections to my carrying these patches in the ext4 git tree? Changes since -v1: - Added explanatory comments in update_time() regarding i_ts_dirty_days - Fix type used for days_since_boot - Improve SMP scalability in update_time and ext4_update_other_inodes_time - Added tracepoints to help test and characterize how often and under what circumstances inodes have their timestamps lazily updated Theodore Ts'o (5): fs: split update_time() into update_time() and write_time() vfs: add support for a lazytime mount option vfs: don't let the dirty time inodes get more than a day stale vfs: add lazytime tracepoints for better debugging ext4: add support for a lazytime mount option fs/btrfs/inode.c | 10 +++++ fs/ext4/inode.c | 48 ++++++++++++++++++-- fs/ext4/super.c | 9 ++++ fs/fs-writeback.c | 42 +++++++++++++++++- fs/inode.c | 104 +++++++++++++++++++++++++++++++++++++++----- fs/proc_namespace.c | 1 + fs/sync.c | 7 +++ fs/xfs/xfs_iops.c | 39 +++++++---------- include/linux/fs.h | 5 +++ include/trace/events/ext4.h | 29 ++++++++++++ include/trace/events/fs.h | 56 ++++++++++++++++++++++++ include/uapi/linux/fs.h | 1 + 12 files changed, 313 insertions(+), 38 deletions(-) create mode 100644 include/trace/events/fs.h -- 2.1.0 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs